Method of preparing a chromatography matrix

A method of preparing a chromatography column, which method comprises the steps of

• (a) providing an aqueous solution of a gellable polysaccharide;
• (b) substituting part of the hydroxyl groups of the polysaccharide in the aqueous solution with groups that are not susceptible to nucleophilic attack once substituted;
• (c) providing essentially spherical droplets of the substituted polysaccharide solution from step (b);
• (d) forming a gel of the essentially spherical droplets;
• (e) cross-linking the gel by adding a cross-linking agent to form a porous cross-linked polysaccharide chromatography matrix;
• and
• (f) packing said porous cross-linked polysaccharide chromatography matrix in a chromatography column;
• wherein said porous cross-linked polysaccharide chromatography matrix allows higher flow rate of said column than matrix made from non-substituted polysaccharide.